linux-kernel - [PATCH] KVM: SEV: Clear the pages pointer in sev_unpin

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Message-Id: <20220627161123.1386853-1-pgonda@google.com>
Date:   Mon, 27 Jun 2022 09:11:23 -0700
From:   Peter Gonda <pgonda@...gle.com>
To:     kvm@...r.kernel.org
Cc:     Peter Gonda <pgonda@...gle.com>, Greg Thelen <gthelen@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] KVM: SEV: Clear the pages pointer in sev_unpin_memory

Clear to the @pages array pointer in sev_unpin_memory to avoid leaving a
dangling pointer to invalid memory.

Signed-off-by: Peter Gonda <pgonda@...gle.com>
Cc: Greg Thelen <gthelen@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <seanjc@...gle.com>
Cc: Tom Lendacky <thomas.lendacky@....com>
Cc: kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
 arch/x86/kvm/svm/sev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 309bcdb2f929..485ad86c01c6 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -452,6 +452,7 @@ static void sev_unpin_memory(struct kvm *kvm, struct page **pages,
 	unpin_user_pages(pages, npages);
 	kvfree(pages);
 	sev->pages_locked -= npages;
+	*pages = NULL;
 }
 
 static void sev_clflush_pages(struct page *pages[], unsigned long npages)
-- 
2.37.0.rc0.161.g10f37bed90-goog